Semiconductor module cooling system
A cooling apparatus includes a discrete module and a plastic housing. The discrete module includes a semiconductor die encapsulated by a mold compound, a plurality of leads electrically connected to the semiconductor die and protruding out of the mold compound and a first cooling plate at least partly uncovered by the mold compound. The plastic housing surrounds the periphery of the discrete module. The plastic housing includes a first singular plastic part which receives the discrete module and a second singular plastic part attached to a periphery of the first plastic part. The second plastic part has a cutout which exposes at least part of the first cooling plate and a sealing structure containing a sealing material which forms a water-tight seal around the periphery of the discrete module at a side of the discrete module with the first cooling plate.
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The instant application relates to semiconductor modules, and more particularly to cooling systems for semiconductor modules.
BACKGROUNDPower modules with double-side cooling significantly improve the thermal performance of the package by reducing thermal resistance, and thereby increasing the power density of the entire system. However, power modules with double-sided cooling present a challenge with regard to integrating a heat-sink with the module. The design of the cooler often is a critical issue in achieving the highest possible performance. For example, the cooling fluid should be distributed in two different channels above and below the power modules included in the package to increase the thermal performance of the package. Also, the entire system must be watertight. The heat sink should be robust, low-cost and lightweight.
Conventional double-sided module cooling technologies require additional parts such as O-rings and bolts or screws to achieve a water-tight system. Conventional aluminum coolers also use thicker aluminum blocks. Still further components are typically needed to achieve a watertight heat-sink and bi-directional coolant distribution. These additional parts increase the system weight and cost and still present a real risk of fluid leakage. Furthermore, the need for many assembly steps increases production cost.
SUMMARYEmbodiments described herein provide a cooling system for molded semiconductor modules without using bolt connections or O-rings. The cooling system described herein has a much lower risk of fluid leakage and higher design flexibility compared to conventional power module cooling systems, significantly reducing system cost, the number of assembly steps and system weight.
According to an embodiment of a cooling apparatus, the cooling apparatus comprises a plurality of discrete modules and a plastic housing. Each module comprises a semiconductor die encapsulated by a mold compound, a plurality of leads electrically connected to the semiconductor die and protruding out of the mold compound and a first cooling plate at least partly uncovered by the mold compound. The plastic housing surrounds the periphery of each module to form a multi-die module. The plastic housing includes a first singular plastic part which receives the modules and a second singular plastic part attached to a periphery of the first plastic part. The second plastic part has cutouts which expose the first cooling plates and a sealing structure containing a sealing material which forms a water-tight seal around the periphery of each module at a side of the modules with the first cooling plates.
According to an embodiment of a method of manufacturing a cooling apparatus, the method comprises: receiving a plurality of modules by a first singular plastic part, each of the modules comprising a semiconductor die encapsulated by a mold compound, a plurality of leads electrically connected to the semiconductor die and protruding out of the mold compound, and a first cooling plate at least partly uncovered by the mold compound; attaching a second singular plastic part to a periphery of the first plastic part to form a plastic housing, the plastic housing surrounding a periphery of each module to form a multi-die module, the second plastic part having cutouts which expose the first cooling plates and a sealing structure facing a side of the modules with the first cooling plates; and filling the sealing structure with a sealing material which forms a water-tight seal around the periphery of each module at the side of the modules with the first cooling plates.
According to another embodiment of a cooling apparatus, the cooling apparatus comprises a plurality of discrete modules each of which comprises a semiconductor die encapsulated by a mold compound, a plurality of leads electrically connected to the semiconductor die and protruding out of the mold compound, and a first cooling plate at least partly uncovered by the mold compound. The cooling apparatus further comprises a first and second plastic housing each of which surrounds a periphery of a different subset of the modules to form separate multi-die modules. Each of the plastic housings comprises a first singular plastic part which receives the corresponding subset of modules and a second singular plastic part attached to a periphery of the first plastic part, the second plastic part having cutouts which expose the first cooling plates and a sealing structure containing a sealing material which forms a water-tight seal around the periphery of each module at a side of the modules with the first cooling plates. The cooling apparatus also comprises first, second and third covers. The first cover is attached to a periphery of the second plastic part of the first plastic housing so as to form a water-tight seal with the second plastic part of the first plastic housing and an enclosed cavity between the first cover and the second plastic part, the enclosed cavity configured to permit fluid flow over the first cooling plates of each discrete module included in the first plastic housing. The second cover is interposed between and attached to the first and the second plastic housings. The second cover is attached to a periphery of the second plastic part of the second plastic housing so as to form a water-tight seal with the second plastic part of the second plastic housing and an enclosed cavity between the second cover and the second plastic part, the enclosed cavity configured to permit fluid flow over the first cooling plates of each discrete module included in the second plastic housing. The third cover is attached to a side of the second plastic housing opposite the second cover.
Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. The features of the various illustrated embodiments can be combined unless they exclude each other. Embodiments are depicted in the drawings and are detailed in the description which follows.
According to embodiments described herein, a cooling system for molded semiconductor modules is provided. Each semiconductor module includes a semiconductor die encapsulated by a mold compound, a plurality of leads electrically connected to the semiconductor die and at least partly uncovered by the mold compound, and a first cooling plate at least partly uncovered by the mold compound. The cooling system further comprises a plastic housing which surrounds the periphery of each module to form a multi-die module. The plastic housing includes a first singular plastic part which receives the modules and a second singular plastic part attached to a periphery of the first plastic part. The second plastic part has cutouts which expose the first cooling plates and a sealing structure containing a sealing material which forms a water-tight seal around the periphery of each module at a side of the modules with the first cooling plates.
In the case of double-sided cooling, each discrete module has a second cooling plate at a side opposite the first cooling plate and the first plastic part has cutouts which expose the second cooling plates. The first plastic part also has a sealing structure containing additional sealing material which forms a water-tight seal around the periphery of each module at the side of the modules with the second cooling plates. A cover can be attached to the periphery of one or both plastic parts to form a water-tight seal with the corresponding plastic part. An enclosed cavity between each cover and the corresponding plastic part permits fluid flow over the cooling plates of each discrete module. The cooling system does not require bolt connections or O-rings. As such, the cooling system has a much lower risk of fluid leakage and higher design flexibility compared to conventional power module cooling systems, significantly reducing system cost, the number of assembly steps and system weight.
The semiconductor dies) included in each discrete module 100 and connected to the corresponding leads 104 can be any type of semiconductor die requiring liquid cooling during operation such as an IGBT (insulated gate bipolar transistor) die, power MOSFET (metal oxide semiconductor field effect transistor) die, JFET (junction field effect transistor) die, GaN die, SiC die, thyristor die, power diode die, etc. More than one semiconductor die can be included in some or all of the modules 100, as well as passive components. The semiconductor dies can form any type of desired circuit such as a half-bridge, full-bridge or 3-phase circuit, etc.
Each discrete module 100 can have a single cooling plate 106 at one side of the module 100, or a pair of spaced apart cooling plates 106 at opposing sides of the module 100 with the corresponding semiconductor die interposed between the pair of cooling plates 106 (the bottom module cooling plates are out of view in
In
The plastic housing 200 includes first and second singular (i.e. individual or discrete) plastic parts 204, 206. The plastic parts 204, 206 can be formed using any standard process such as injection molding, 3-D printing, etc. In general, the first singular plastic part 204 receives the modules 102. The second singular plastic part 206 is attached to the periphery 208 of the first plastic part 204 and has cutouts 210 which expose the first cooling plates 106 of the modules 102. The second plastic part 206 also has a sealing structure 212 for containing a sealing material which forms a water-tight seal around the periphery 212 of each module 102 at a side of the modules 102 with the first cooling plates 106 after assembly.
In the case of a double-side cooling configuration as shown in
Both plastic parts 204, 206 have one or more openings 218 along their respective lengths for injecting the sealing material into the sealing structure 212, 216 of the corresponding plastic part 204, 206. The plastic parts 204, 206 can also include one or more openings 220 at one or both ends of the plastic parts 204, 206 for allowing fluid flow from one side of the housing 200 to the other side after covers are attached to both sides of the assembled plastic housing 200. The first plastic part 204 can be attached to the second plastic part 206 using any standard plastic attach process such as plastic welding, laser welding, heat sealing, gluing, etc.
The leads 104 of each discrete module 104 remain at least partly uncovered by the plastic housing 200. In the case of lead-frame type or similar leads, the leads 104 of each discrete module 102 protrude out of the plastic housing 200 as shown in
Further according to the double-sided cooling embodiment shown in
In
A first cover 400 is attached to the periphery of the second plastic part 406 and forms a water-tight seal with the second plastic part 206. An enclosed cavity 406 is formed between the first cover 400 and the second plastic part 206. The enclosed cavity 406 is configured to permit fluid flow over the first cooling plates 106 of each discrete module 102. The second cover 402 is attached to a periphery of the first plastic part 204 and forms a water-tight seal with the first plastic part 204. An enclosed cavity 406 between the second cover 402 and the first plastic part 204 is configured to permit fluid flow over the second cooling plates 106 of each discrete module 102.
On or both covers 400, 402 have at least one port 410 for permitting fluid flow into and out of the cooling apparatus 404. The fluid flows within the enclosed cavities 406, 408 formed between the respective covers 400, 402 and plastic parts 204, 206 of the plastic housing 200, traversing over the cooling plates 106 of the discrete modules 102. Each plastic part 204, 206 of the plastic housing 200 can have one or more openings 220 at one or both ends of the plastic part 204, 206 for allowing fluid flow from one side of the plastic housing 200 to the other side after the covers 400, 402 are attached to both sides of the assembled plastic housing 200. In one embodiment, the covers 400, 402 are made of plastic and attached to the periphery of the respective plastic parts 204, 206 of the plastic housing 200 by any standard plastic attach process such as plastic welding, laser welding, heat sealing, gluing, etc.
The first cover 506 is attached to the periphery of the second plastic part of the first plastic housing 502 so as to form a water-tight seal with the second plastic part of the first plastic housing 502 and an enclosed cavity 512 between the first cover 506 and the second plastic part e.g. as previously described herein in connection with
The second cover 508 is interposed between and attached to the first and the second plastic housings 502, 504. The second cover 508 is attached to the periphery of the second plastic part of the second plastic housing 504 so as to form a water-tight seal with the second plastic part of the second plastic housing 504 and an enclosed cavity 514 between the second cover and the second plastic part e.g. as previously described herein in connection with
The second cover 508 is attached to the periphery of the first plastic part of the first plastic housing 502 at a side of the first plastic housing 502 facing away from the first cover 506 so as to form a water-tight seal with the first plastic part of the first plastic housing 502 and an enclosed cavity (out of view) between the second cover and the first plastic part e.g. as previously described herein in connection with
The third cover 510 is attached to the periphery of the first plastic part of the second plastic housing 504 at a side of the second plastic housing facing away from the second cover 508 so as to form a water-tight seal with the first plastic part of the second plastic housing 508 and an enclosed cavity (out of view) between the third cover 510 and the first plastic part. The enclosed cavity between the third cover and the first plastic part of the second plastic housing 508 is configured to permit fluid flow over second cooling plates 106 of each discrete module included in the second plastic housing 504 which are disposed at a side of the modules facing away from the second cover 508.
According to the embodiment shown in
The fourth cover 604 is attached to the periphery of the first plastic part of the third plastic housing 602 at a side of the third plastic housing 602 facing away from the third cover 510 so as to form a water-tight seal with the first plastic part of the third plastic housing 602 and an enclosed cavity (out of view) between the fourth cover 604 and the first plastic part. The enclosed cavity between the fourth cover 604 and the first plastic part of the third plastic housing 602 is configured to permit fluid flow over second cooling plates 106 of each discrete module included in the third plastic housing 602 which face away from the third cover 510.
The cooling apparatus covers can include surface features which enhance the flow of fluid with the corresponding cooling apparatus.
Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper” and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc. and are also not intended to be limiting. Like terms refer to like elements throughout the description.
As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open-ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
With the above range of variations and applications in mind, it should be understood that the present invention is not limited by the foregoing description, nor is it limited by the accompanying drawings. Instead, the present invention is limited only by the following claims and their legal equivalents.
Claims
1. A cooling apparatus, comprising:
- a discrete module comprising: a semiconductor die encapsulated by a mold compound; a plurality of leads electrically connected to the semiconductor die and protruding out of the mold compound; and a first cooling plate at least partly uncovered by the mold compound; and
- a plastic housing surrounding a periphery of the discrete module, the plastic housing comprising: a first singular plastic part which receives the discrete module; and a second singular plastic part attached to a periphery of the first plastic part, the second plastic part having a cutout which exposes at least part of the first cooling plate and a sealing structure containing a sealing material which forms a water-tight seal around the periphery of the discrete module at a side of the discrete module with the first cooling plate.
2. The cooling apparatus of claim 1, wherein the sealing structure of the second plastic part comprises a groove formed in the second plastic part which surrounds the periphery of the discrete module at the side of the discrete with the first cooling plate, and wherein the sealing material fills the groove.
3. The cooling apparatus of claim 2, wherein a part of the second plastic part disposed interiorly from the groove contacts the side of the discrete with the first cooling plate to prevent the sealing material from leaking onto the first cooling plate.
4. The cooling apparatus of claim 1, further comprising:
- a first cover attached to a periphery of the second plastic part and forming a water-tight seal with the second plastic part; and
- an enclosed cavity between the first cover and the second plastic part configured to permit fluid flow over the first cooling plate of the discrete module.
5. The cooling apparatus of claim 1, wherein the discrete module has a second cooling plate at a side opposite the first cooling plate, and wherein the first plastic part has a cutout which exposes at least part of the second cooling plate and a sealing structure containing additional sealing material which forms a water-tight seal around the periphery of the discrete module at the side of the discrete module with the second cooling plate.
6. The cooling apparatus of claim 5, wherein the sealing structure of the first plastic part comprises a groove formed in the first plastic part which surrounds the periphery of the discrete module at the side of the discrete module with the second cooling plate, and wherein the additional sealing material fills the groove in the first plastic part.
7. The cooling apparatus of claim 6, wherein a part of the first plastic part disposed interiorly from the groove contacts the side of the discrete module with the second cooling plate to prevent the additional sealing material from leaking onto the second cooling plate.
8. The cooling apparatus of claim 5, further comprising:
- a second cover attached to a periphery of the first plastic part and forming a water-tight seal with the first plastic part; and
- an enclosed cavity between the second cover and the first plastic part configured to permit fluid flow over the second cooling plate of the discrete module.
9. The cooling apparatus of claim 5, wherein the first singular plastic part has one or more openings along the length of the first singular plastic part configured to inject the sealing material into the sealing structure of the first singular plastic part.
10. The cooling apparatus of claim 1, wherein the mold compound is an epoxy.
11. The cooling apparatus of claim 1, wherein the leads are formed from a lead-frame.
12. The cooling apparatus of claim 1, wherein the leads are gull-wing, J-lead or flat leads.
13. The cooling apparatus of claim 1, wherein the semiconductor die is an IGBT die, a power MOSFET die, a JFET die, a GaN die, a SiC die, a thyristor die, or a power diode die.
14. The cooling apparatus of claim 1, wherein a plurality of semiconductor dies is included in the discrete module.
15. The cooling apparatus of claim 1, wherein the semiconductor die forms part of a half-bridge circuit, a full-bridge circuit or a 3-phase circuit.
16. The cooling apparatus of claim 1, wherein the cooling plate has surface structures configured to increase the turbulence of fluid flowing over the cooling plate.
17. The cooling apparatus of claim 16, wherein the surface structures are pins, fins or an intentionally roughened surface.
18. The cooling apparatus of claim 1, wherein the first and the second singular plastic parts include one or more openings at one or both ends of the first and the second singular plastic parts configured to allow fluid flow from one side of the plastic housing to an opposite side of the plastic housing.
19. The cooling apparatus of claim 1, wherein the discrete module is seated in a recessed region of the first plastic part.
20. The cooling apparatus of claim 1, wherein the second singular plastic part has one or more openings along the length of the second singular plastic part configured to inject the sealing material into the sealing structure of the second singular plastic part.
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Type: Grant
Filed: Feb 23, 2018
Date of Patent: Feb 5, 2019
Patent Publication Number: 20180182643
Assignee: Infineon Technologies AG (Neubiberg)
Inventors: Inpil Yoo (Unterhaching), Andreas Grassmann (Regensburg)
Primary Examiner: Mamadou Diallo
Application Number: 15/903,913
International Classification: H01L 21/48 (20060101); H01L 23/473 (20060101); H01L 23/498 (20060101); H01L 23/18 (20060101); H01L 21/54 (20060101); H01L 23/373 (20060101); H01L 23/44 (20060101); H01L 21/56 (20060101); H01L 23/08 (20060101); H01L 23/367 (20060101); H01L 23/31 (20060101);